Apparatus for and method of rapid transmission of telegraphic messages



July 29. 1924.- 1,503,250

P. E. SABINE ET AL APPARATUS FOR AND METHOD OF RAPID TRANSMISSION OF TELEGRAPHIC MESSAGES Filed Aug. '7. 1920 Patented July 29, 1924. J

UNTD sures PATENT o FicE.

PAUL E. sannvn AND WILLIAM F. rnrnmvrnnorenimvn, rumors, Ass'rGNons 'ro sari) rant E. SABI-NE, AS TRUSTEE.

APPARATUS FOR AND METHOD To all whom it may concern:

Be it known that we, PAUL E. SABINE and WVILLI M I FRIEDMAN, citizens of the United States, residing at Geneva, Illinois, have invented certain new and useful Improvements in Apparatus for and Methods of Rapid Transmission of Telegraphic Messages, of which the following is a specification.

This invention relates to mechanical means for sending and receivingwireless messages and to anew method of. carrying out this operation, the-purpose being to simplify the work and increase the speed of such transmission of messages; it also relates to apparatus for wireless relaying of signals from one wire system to another, and the method of accomplishing this result; alsoto the transmission by radio of such impulses as are used for operating high speed printing telegraphs; it is a further object to produce a device by which a message received as if composed of impulses of one kind only, willbe translated into impulses of two kinds; and such further objects, advantages and capabilities as vwill later more" fully appear.

Our invention furtherresides in the combination, construction andearrangement of parts illustrated in the accompanying drawing, and while we have showntherein a preferred embodiment we desire the same to be understood as illustrative only and not as limiting our invention.

At present the transmission of code signals by wireless requires two modifications of-the transmitting electric current for the formation of letters and symbols of the transmitted messages, while by our invention such transmission may be accomplished with only a single modification. In ordinary telegraphing thesemodifications .consist of dots and dashes produced by short and long periods during which the signalling circuit is closed by the telegraphic key. In the so called stop and start system of the printing telegraph. positive and negative pulses of electric current are made to 1)l'07 duce' opposite effects upon a receiving relay. It is to the latter system that the present invention is applicable.

lVe will assume that each one of the letters of the alphabet and the various symbols necessa y in telegraphic communicat on c n tarp- .5 am

0F RAPID TRANSMISSION or'rE nennrrrro MESSAGES.

Application filed August 7, 1920. Serial No. 401,935.

be represented respectively by one ofthe thirty-two possible arrangements of positive andnegative impulses of a group of five impulses of both kinds. posltive impulses by a and a negative 1mpulseby b, combinations by which the letters'of the word the may be represented, are as follows: 7

7 aaaab H aabab In the present invention the transmitting device will supply only the positive impulses. During the interval in which the negative impulses would ordinarily betransmittedQthe sending mechanism is inoperabaaaa tive, the negative impulses being supplied by the receiving mechanism in a manner to be described later. I

In the drawings, annexed hereto and forming a part hereof, Fig. lis adiagrammatic representation of a sending mechanism in accordancewith our invention, while Fig. .2 represents diagrammatically the mechanism of the receiving station. The following description and diagrams are specifically for the case in which the energy for the production of signals is transmitted without wires. It applies with slight alteration. to the case in which the transmission of energy, is by means of electric oscillations along wires, and the response ofthe receiving apparatus is conditioned upon its being tunedto the frequency of these oscillations.

. Referring more in detail to the mechanism shown inthe drawings, E denotes a generator of radio frequency continuous electromagnetic oscillations connected in the ordinary manner to, the antenna circuit of the sending station, the coil S of which is tuned to be inresonance with E. The polarized relay R of the printing telegraph is placed inthe antenna circuit, taking the Indicating a place-of the sending key of ordinary hand transmission. .Thisrelay R'is operated by thepositive andv negative impulses coming over the line L, in which is located the mechanical sending means. The two positions of the armature of the polarized relay correspond with the two' positions "of the key in the ordinary method of signalling by dots and dashes, position n corresponding to the open keyand position to the closed,

The mechanism at the receiving end, shown in Fig. 2, will now beconsidered, in place of the receiving telephone, commonly used, relay R is. substituted. The armature of this relay is normally held in position a, in engagement with a contact a so as to close the circuit to line L through one of the contacts of the rotating device W. When incom ng signals energ ze the solenoid of relay R, the armature is pulled over into position p to close the circuit toline L creasing the amplitudeof the electromag. n'etic waves being radiated. When a p0si-- tive impulseactuates-[the relay,7the armature is pulled to the position 32. The waves will then be radiated with full amplitude,

' having the frequency of the generator E and the tuned circuit S. An ordinary re- I ce-iving station with antenna tuned to the frequency E will then receive a series of signals inwhich the'positive impulses coming over the line L are represented by sounds in the telephone receiver, and the negative impulses by silences, because, by

f the arrangement shown, the negative impulses are not tuned tothe frequency E, and will, therefore, not be heard. In other words, so far as the receiving station is concerned, the sending station can transmit only the positive impulses-and suppresses the negative impulses. The word the will then be represented thus T H E At the receiving station, the incoming I signals, corresponding to'the positive im pulses of the sendingstatioh, pull the armature of the relay to the position p, connecting the line L to the positive end ofa source of electric current. The electromagnetllgl referred to above, is located in this circuit, and is, therefore, energized only by the positive impulsesproduced by the incoming signals. The purpose of this elecmasn w l appear later, c

l The rotor W is simply a'device which the line L is put into contact withthejnegative end of'a battery five times during, Bach revolution ofthe rotor, provided the armature of the relay] R is on the contact a o e pond n f6 Po iti n T e rotor W car ie a series, ofgcontacts C C C C and C spaced 60apart about th'e axis 9? t e rotor, he int rval "Et n C and C being 120 and corresponding to the interval between letters. Attached to each of these contacts is a piece of soft iron which is. a ted on by the cctromagnet M asthe rotor turns past the magnet, provided the armature of relay R is in position 79. If there is approximate synchronism between the sending and receiving mechanisms, the tendency of the electromagnet M will be to advance or retard the rotor W by attraction of the soft iron pieces. This will, therefore, tend to produce exact syn: chronism between the sending and receiving mechanisms. Approximate synchronism of these mechanisms may be attained by any one of a number of well known me chanical devices.

The rotor should be driven at a con-- stant speed by an automatically governed driving mechanism, its speed being adjust ed so that the negative impulses imparted to the line L through the contacts, B and n are" synchronous with the impulses received from .the line L at the transmitting station. If we suppose. that the letter T s is being transmitted, this will be represented by four positive impulses and a negative Impulse, wh ch are transmitted by the sending station. Since the positive impulses are transmitted as electrical oscillations of frequency End the receiving sta- 'tion is tuned to the same frequency these four positive impulses will be picked up by this receiving apparatus, and the. negative impulse being at a different frequency will not be picked up. The relay R will then be energilzedby four pulses of current followed by a time interval in which no current flows, this being of the length of one pulse, corresponding to the negative impulse. The armatureof relay R will then make four contacts'with Z2 followedby one with a". The line L will accordingly receive the four positive impulses and the one negative corresponding to the letter T.

llO

a modification of the above described apparatus, the single electromagnet M may be replaced by s1 magnets, spaced at points 60 apart about the axis of rotation of the rotor WV. -A separate relay, operating a local battery circuit, and connected in series with the solenoid of'relay B, may be provided for energizing the electromagnet M or the substituted six electromagnets in the event that such are used.

It appears that for successful operation two conditions are necessary; first the adjustment of the brushing contact B must be such that it will always touch a moving contact C at such times as it is possible for an electromagnetic impulse to be received to actuate the relay R. Then at suh of these times as there is no electromagnetic impulse actually received there will be a negative ipulse s plil ed to. he line L through the contacts C, B and a. The blank position on the rotor, which has no contact, must be at the contact B at the time which corresponds to the interval allowed, by the sending machine, between letters or symbols. This condition is met by proper initial adjustment of the brush E.

Second, there must be exact synchronism between the mechanism operating the sending key and the rotation of W. This condition is met as indicated above, by securing an approximate synchronism of sending and receiving mechanisms, by well known mechanicaldevices, and then securing exact synchronism by means ofthe action of electro: magnet M on the iron pieces secured to the rotor If the pulses'through M are in exact step with the soft iron pieces attached to the rotor, then the force between the magnet and the iron has no effect either in retarding or accelerating the motion of the rotor. If, however, the position of the soft iron pieces is slightly in advance of the magnet at the instant the incoming signal opcrates, then the pull of the magnet will retard the rotor W; conversely, if the pole piece is slightly behind the magnet M at the instant of the arrival of the signal, then the force is such as to accelerate the rotor. In' this way, the rotor is automatically kept in exact step with the incoming signals. Other methods of securing the same result may be employed.

Plainly L may represent the receiving end of a wire transmission line. It is also the sending end of a wireless system of transmission; similarly L is the receiving end of a wireless system, and may be the sending end of a wire system. The impulses which actuate the wireless apparatus may originate locally or at a distance, and thus transmitted'along L may be received locally or at a distance. Therefore our invention provides a means by which messages may be directly and automatically relayed by wire less from one wire system to an system. g

It appears also that the apparatus and the method are applicable to any wire system of telegraphy in which the transmission of energy for producing the signals is by means of electric oscillations and inwhich other wirethe response of the receiving apparatus is conditioned upon its being tuned to the frequency of such oscillations, Therefore, while the foregoing description and diagrams have referred specifically to the case in whichthc electromagnetic oscillations are transmitted without wires, they apply equally to the case in which these oscillations are carried on wires and the application to the latter is a part of our invention.

It is, of course, understood that the specific description of structure and methods set forth above may be departed from with 'Ineans operated.

out departing from the spirit of our inven-' tion as set forth in this specification and the appended claims.

Having now described our invention. we claim:

1. In telegraphic systems comprising a transmitting means operating with two clifferent kinds of impulses and transmitting only one kind thereof to a receiving means, and receiving means supplying the untransmitted kind of impulses whereby the receiving means operates with two different kinds of impulses similar to these with which the transmitting means operated.

2. Inapparatus for transmitting messages comprising sending and receiving devices, saidzsending device having a generator of electromagnetic oscillations, a tuned circuit, means operating with two kinds of impulses and: having means for suppressing one of said kinds of impulses, means to transmit the other of said kinds of impulses as electro-magnetic waves of a definite 'fre uency and amplitude capable of effecting tie operation. of the receiving device.

3. In apparatus for transmitting messages comprising sending and receiving devices, said sending device having a generatorof electro-magnetic oscillations, a tuned circuit, means operatingwith two kinds of impulses and having means for suppressing one of said kinds of impulses, means to transmit with two diiferentkinds of impulses similar to those with which the transmitting 4. In apparatus for transmitting messages comprising sending and receiving devices,

said sending device having means for producingand,transmitting tuned electric oscillations by means of a suitable 'medium, means for impressing a selected kind of impulses of different kinds of impulses upon the transmitting means whereby the receiving device operates with like impulses, said receiving means having means for. supplying impulses of a different kind, whereby the receiving means operates with different kinds of impulses similar to those with which the sending device operated.

5. In apparatus for transmitting messages comprising sending and receiving devices,

means operating with impulses of different kinds and causing a selected kind thereof to be transmitted by the sending device to the receiving device, means for causing the receiving device to furnish impulses corresponding to the different kinds of impulses operating in the sending device.

6, In anapparatus fort ansmitting mess sages comprisingsending and receiving devices, said sending means having means for transmitting electricalenergy to the receiving device by means of a suitable medium capable of transmitting electric oscillations, means operating with two different kinds of electrical impulses and to suppress one thereof and to impress the other thereof upon the transmitted energy, and means to cause the receiving device to furnish two kinds of impulses similar to those operating in the sending device. 4

7 In an apparatus for transmitting messages comprising sendingandreceiving devices, said sending means havingmeans for transmitting electrical energy to. the receiving devicebv means of a suitable medium capable of transmitting electro-magnetic oscillations, means operating with two .7 dif- 'ferent kinds of electrical impulses and to suppress one, thereof and to impress the other thereof upon the transmitted energy, and means to causethe receiving device to supply impulses corresponding to two kinds of impulses operating in the sending device, the last named means including means for synchronizing the receiving device with thesending device. v

8. In an apparatus for transmitting messages comprising sending and receiving devices, said sending means having means for transmitting electrical energy to the receiving device by means of a suitable .medium capable of transmittingelectro-magnetic oscillations, means operating with two different kinds of electrical impulses to suppress one thereof and to impress the other thereof upon the transmitted energy, ,and

means to cause the receiving device to supply impulses corresponding to two kinds of impulses operating n thesendlng device, the last named means having means for substantially synchronizingthe receiving device with the sending device, and means for automatically adjusting the synchronizing means to effect exact synchronism with the sending device. 7

9. In apparatus fortransmitting messages comprising sending and receiving devices,

said sending device having means for radiating electro-magnetic oscillations, said oscillations being transmitted by a suitable medium to the receiving devicefmeans for modifying the frequency of said oscillations, said modifications being affected by a suc- ,cession of two kinds of impulses, said recciving device having means for reproducing impulses of the kind that eifected the transmission of theunmodified oscillations andfmeans for supplying impulses like those that modifiedithe frequency; ofthe electromagnetic oscillations.

10. In apparatus for transmitting mes sages comprising sending and receiving demessed sending .meaas, hamsmaa a receiving two diflerent kinds of impulses, means for transmitting only one kind of said impulses to the receiving device, said receiving device reproducing the other kind of impulses whereby the received and reproduced impulses eifect recording of impulses in accordance with the impulses received by the sending device.

11. In apparatus for transmitting messages comprising a generator of electrical oscillations, means for transmitting said oscillations, means for modifying parts of said oscillations, said means being affected by different kinds of impulses and effecting non-transmission of a kind of said impulses atthe instants of effecting said modifying of said parts of said oscillations.

12. 'lhe method of transmitting and recording messages, consisting of transmitting one of "two different kinds of impulses, receiving the transmitted'kind of impulses, and reproducing the other kind of impulses whereby impulses of two kinds are recorded.

13. The method of transmitting and recording messages, consisting of transmitting one of two different kinds of impulses and of modifying the frequency and amplitude of electro-magnetic oscillations by the other kind of impulses sothat they will not be received by a receiving device receiving the I transmitted impulses and automatically supplying impulses corresponding to the modified impulses in the sending device. I

14.. In apparatus of the class described,

mechanism for producing impulses of two kinds,'means for producing electro-magnetic oscillations corresponding intime location to these two kinds, but having different frequencies and amplitudes, means for transmitting and receiving impulses correspondradiating by the other kind of said impulses electro-magnetic oscillations .of such frequency and amplitude as will not be received by the wireless receiving apparatus, supplying by the receiving mechanism of the wireless system, impulses of the second kind, and transmitting to the second wire system impulses of both kinds, corresponding in time location to those of the first wire system.

16- In apparat f tran mi t ng messase scas era aa a n r t Of is r v of said impulses.

17. In apparatus for transmitting mes sages comprising means for effecting successive impulses consonant With electro-magnetic oscillations received by said means from a sending device, and means for supplying impulses corresponding in time location to impulses afiecting the sending device but not received by the receiving device.

In Witness whereof, We hereunto subscribe our names to this specification in the pres- 15 once of two Witnesses.

PAUL E. SABINE. WILLIAM F. FRIEDMA N.

Witnesses:

FRED W. KRANZ, FANNIE J. EvERs. 

